HENRY

In PNAS: Intraspecific phylogenetic analysis of Siberian woolly mammoths using complete mitochondrial genomes (doi):

We report five new complete mitochondrial DNA (mtDNA) genomes of Siberian woolly mammoth (Mammuthus primigenius), sequenced with up to 73-fold coverage from DNA extracted from hair shaft material. Three of the sequences present the first complete mtDNA genomes of mammoth clade II.

Analysis of these and 13 recently published mtDNA genomes demonstrates the existence of two apparently sympatric mtDNA clades that exhibit high interclade divergence. The analytical power afforded by the analysis of the complete mtDNA genomes reveals a surprisingly ancient coalescence age of the two clades, ~1–2 million years, depending on the calibration technique.

Furthermore, statistical analysis of the temporal distribution of the ¹⁴C ages of these and previously identified members of the two mammoth clades suggests that clade II went extinct before clade I. Modeling of protein structures failed to indicate any important functional difference between genomes belonging to the two clades, suggesting that the loss of clade II more likely is due to genetic drift than a selective sweep.

John Hawks has a nicely detailed discussion about handling exponential growth in demographic models. Very interesting, and hopefully he’ll keep them coming:

Exponential growth is a feature of current human populations, and was may represent how the human population behaved during some episodes of its demographic history. However, “exponential” can mean different things to different people, if you’re not used to thinking mathematically about growth. So I need to lay out some definitions…

Su et al in today’s PLoS One show that Asiatic honeybees can understand the “Waggledance” (video) language of European honeybees:

The honeybee waggle dance, through which foragers advertise the existence and location of a food source to their hive mates, is acknowledged as the only known form of symbolic communication in an invertebrate. However, the suggestion, that different species of honeybee might possess distinct ‘dialects’ of the waggle dance, remains controversial. Furthermore, it remains unclear whether different species of honeybee can learn from and communicate with each other.

This study reports experiments using a mixed-species colony that is composed of the Asiatic bee Apis cerana cerana (Acc), and the European bee Apis mellifera ligustica (Aml). Using video recordings made at an observation hive, we first confirm that Acc and Aml have significantly different dance dialects, even when made to forage in identical environments. When reared in the same colony, these two species are able to communicate with each other: Acc foragers could decode the dances of Aml to successfully locate an indicated food source.

We believe that this is the first report of successful symbolic communication between two honeybee species; our study hints at the possibility of social learning between the two honeybee species, and at the existence of a learning component in the honeybee dance language.

Very very neat indeed. The full paper is available here: East Learns from West: Asiatic Honeybees Can Understand Dance Language of European Honeybees (doi), and ScienceDaily coverage is here.

Margaret Talbot in The New Yorker talks about “the woman behind the world’s chattiest Parrots”, Irene Pepperberg:

As the crowd at the Midwest Bird Expo waited for the cognitive scientist Irene Pepperberg to take the podium, the hum of human chatter was punctuated by the sound of parrots whooping it up—twittering and letting loose with wolf whistles, along with the occasional full-out jungle squawk. The birds, many of them for sale, were displayed in cages just beyond the curtained-off stage, which was inside the main hall of the DuPage County Fairgrounds, in Wheaton, Illinois. Nobody seemed particularly distracted by the commotion. …

Here were admirers who had sent in ten-dollar bills to help support her research with Alex, the African gray parrot that she worked with for thirty years; and here were people who, after Alex died, unexpectedly, of heart arrhythmia, on September 6, 2007, helped form an online community that comes together on the sixth day of every month to reflect about him.

Hanging from the neck of a live goose. Chasing a speeding wheel of cheese down a mountainside. Children smoking. Europeans do all of this and more…. Everyone knows about that annual tempting of fate known as running with the bulls in Pamplona. It’s one of those festivals that make the saner among us scratch our heads in confusion and wonder, “How was that ever a good idea?“

In the latest PNAS, Dating the late prehistoric dispersal of Polynesians to New Zealand using the commensal Pacific rat (doi):

The pristine island ecosystems of East Polynesia were among the last places on Earth settled by prehistoric people, and their colonization triggered a devastating transformation. Overhunting contributed to widespread faunal extinctions and the decline of marine megafauna, fires destroyed lowland forests, and the introduction of the omnivorous Pacific rat (Rattus exulans) led to a new wave of predation on the biota. East Polynesian islands preserve exceptionally detailed records of the initial prehistoric impacts on highly vulnerable ecosystems, but nearly all such studies are clouded by persistent controversies over the timing of initial human colonization, which has resulted in proposed settlement chronologies varying from ~200 B.C. to 1000 A.D. or younger.

Such differences underpin radically divergent interpretations of human dispersal from West Polynesia and of ecological and social transformation in East Polynesia and ultimately obfuscate the timing and patterns of this process. Using New Zealand as an example, we provide a reliable approach for accurately dating initial human colonization on Pacific islands by radiocarbon dating the arrival of the Pacific rat.

Radiocarbon dates on distinctive rat-gnawed seeds and rat bones show that the Pacific rat was introduced to both main islands of New Zealand ~1280 A.D., a millennium later than previously assumed. This matches with the earliest-dated archaeological sites, human-induced faunal extinctions, and deforestation, implying there was no long period of invisibility in either the archaeological or palaeoecological records.

See also: ScienceNews’ coverage which over-hypes the controversy angle.